The present invention relates to a lamp holder, and more particularly to a lamp holder that enables quick and even accurate piercing of an cable connected thereto without using any tool, and may have a fuse, a universal link, a spike, a lamp panel, or a lampshade connected thereto to provide different manners of use thereof.
Generally, a conventional lamp holder, including the lamp holder for a light string, has a structural design that requires traditional ways of assembling, such as fastening by means of screws, tenons and mortises, rivets, supersonic wave, glue, etc. with the help of suitable tools or machines. Thus, the conventional lamp holder has to be manufactured and assembled in a plant or factory. Moreover, following drawbacks are found in the use of the conventional lamp holders:
1. The conventional lamp holders for a light string have fixed specifications and are arranged on the light string at fixed intervals. Therefore, the conventional lamp holders could not be arranged to show special patterns according to specific ornaments to be decorated or personal preference. The light string using the conventional lamp holders are therefore normally used in Christmas time and other festivals only.
2. The conventional lamp holders are not provided with overcurrent protective means, and are therefore not safe for use. There are chances lamp bulbs of high wattage are mounted on the conventional lamp holders to result in overloaded wires and burnt out lamp bulbs.
3. The conventional lamp holders are not provided with means for well fixing the lamp holders to wall panels or other mounting surfaces. Most conventional lamp holders for use outdoors are simply seated in holes or hung on hangers or fixed with nails provided on the wall panels or mounting surfaces. And, it is uneasy to control the length of cables connected to the lamp holders. The lamp holders under strong wind tend to swing and break due to collision with the walls or mounting surfaces, resulting in dark portions on the wall or object surfaces decorated with lamp bulbs to spoil the overall beauty of the decorated walls or objects.
FIG. 12 is a plan view of a currently available lamp holder. As shown, this type of lamp holder is provided at an upper part with piercing terminals that directly pierce through an cable to electrically connect the latter to the lamp holder to save the effort of stripping off the wire sheath. The piercing terminals may be located in the lamp holder at a desired height. In a common practice, the piercing terminals are embedded in a hole in the lamp holder. An cable is connected to the lamp holder by forcing it into the hole to be pierced through by the piercing terminals. And, a barb on each of the piercing terminals functions to retain the cable in the hole. However, in using this type of lamp holder with piercing terminals, it is frequently found the cable is not effectively pierced to electrically connect the lamp holder to conductors in the cable, or the cable subject to an external force tends to separate from the lamp holder easily.
In an improved version of the above-described conventional lamp holder with piercing terminals provided near an open top thereof, screw holes are further provided on the lamp holder close to the piercing terminals. The cable is pressed against the open top of the lamp holder with a hold-down cap. Screws are then extended through the screw holes to force the cable against the piercing terminals, so that the cable is pierced through and fixed in place in the lamp holder by the piercing terminals. This improved type of lamp holder enables better wire connection but requires tools to complete the assembling of the cable to the lamp holder. Moreover, since the screws at two sides of the cable are sequentially tightened, it is possible the cable is not evenly forced against the piercing terminals to result in a misaligned, skidded, or inaccurately pierced cable.
In addition, both of the above two conventional lamp holders have fixed structure and appearance for use in some fixed manners. They are not adapted to associate with other types of fixtures for decorating at different places, and therefore have limited applications.
It is therefore tried by the inventor to develop an improved lamp holder to overcome the drawbacks existed in the conventional lamp holders.
A primary object of the present invention is to provide a lamp holder, to which an cable may be easily connected without using any tool. The lamp holder is so structured that it enables even application of force in the same direction to three serial points on the cable assembled thereto, so that the cable is quickly and accurately pierced through and accordingly, electrically connected to the lamp holder without the risks of becoming misaligned with or skidded off the piercing terminals.
Another object of the present invention is to provide an improved lamp holder that is adapted to associate with different fixtures, such as a sucker, a magnet, a universal link, a spike, a lamp panel, a lampshade, etc., to enable a wide range of applications thereof.
A further object of the present invention is to provide an improved lamp holder having a fuse-connected piercing terminal that can be replaced at any time to ensure the safety in using the lamp holder.
To achieve the above and other objects, the lamp holder of the present invention mainly includes a socket and a cap.
The socket is internally provided at predetermined positions near a rear end thereof with piercing terminals for directly piercing through an cable assembled to the socket and thereby electrically connecting the cable to the lamp holder. The socket is also formed at the rear end with an axially extended and externally threaded first connecting head and a rear flange radially outward extended from a root of the first connecting head. Two wiring notches are oppositely provided on the first connecting head, and a sunken wire groove is provided on the rear end and the rear flange of the socket to extend between the two wiring notches. The wire groove is provided at predetermined positions on a bottom thereof with openings, via which the piercing terminals in the socket are outward projected.
The cap is internally provided with screw threads for engaging with the externally threaded first connecting head of the socket, and has a top recess to provide a bottom surface adapted to press against the cable positioned in the wire groove. The cap has a cap flange radially outward extended from a periphery of an end of the cap facing toward the socket.
When the cable is connected to the lamp holder by positioning the cable in the sunken wire groove and tightening the cap to the first connecting head of the socket, the bottom surface of the top recess of the cap and two areas of the cap flange at two opposite sides of the bottom surface together compress against the cable to evenly apply forces in the same direction to three serial points, that is, a front, a middle, and a rear point, on the cable, so that the cable is quickly pierced through by the piercing terminals projected from the wire groove without becoming misaligned with or skidded off the piercing terminals.
One of the piercing terminals may be connected to a auto-reset fuse to ensure the safety in using the lamp holder.
The top recess of the cap is provided with a universal socket for connecting to a universal joint ball provided at an end of a universal link, such that the lamp holder may be turned by 360 degrees or adjusted to different height relative to a fixed location after the universal link is connected at another end to the fixed location. The lamp holder may therefore be used at different places for different purposes, such as a decorative illumination on a signboard, in a show window, on an exterior wall of a building, or in a garden, or as a general lighting fixture in offices, or other working places, or on streets.